摘要:

Three species of the genusParavortexwere studied. Spermiogenesis involves progressive lengthening of the spermatid. No centriole nor axoneme were found. Thc mature spermatozoon is threadlike, 30μm long and aflagellate. It contains a nucleus, two longitudinal parallel mitochondria, numerous dense bodies limited by a membrane, a row of cortical microtubules and granules. The spatial arrangement of the microtubules wah deduced from a statistical analysis of their number in transverse section. The microtubules are continuous along the length of the spermatozoon and are arranged along a long cone. The granules, not limited by a membrane, are about 25 nm in diameter. They are arranged in a semicircle and represent a new structure for sperm of Platyhclminthes. A statistical comparison demonstrated that two species may be distinguished by the number of their cortical sperm microtubules. This is the tirst ultrastructural study of an aflagellate spermatozoon in the Rhabdocoela. A rickettsia was found inP. cardii

ISSN:0300-3256    

DOI:10.1111/j.1463-6409.1989.tb00442.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Spermiogenesis inUrastoma cyprinae(Graff. 1882) involvcs a progressive lengthening of the spermatid. Free flagella are only transitory. The mature spermatozoon is fusibrm. 45μm in length and 2.5 μm in width. It contains two incorporated axonermes of the flatworm 9+“1” pattern, two elongated mitochondria. an elongated nucleus and a row or cortical longitudinal microtubules. Observations on oogenesis concerncd only the immuturc ovary. lmmature oocytes contain few dense granules and accssory cells were not ohserved. Phylogenetic implications of a biflagellate spermatozoon in a Prolecithophora are important. The presence of two 9 +“1” axonemes confirms thatUrastoma(and the Prolecithophora) belongs to the taxon Trepaxonemata Ehlers. Previous electron microscope studies on spermitozoa of Prolecithophora (four genera) only dealt with aflagellate spermatozoa. On this basis, Ehlers (1985) proposed two autapomorphics for the taxon Prolecithophora: aflagellate spermatozoon and spermatozoal mitochondrial derivatives with abundant membranes. The present observations onUrastomacontradict these two autapomorphics. The taxon Prolecithophora cannot be defined by autapomorphies of the spe

ISSN:0300-3256    

DOI:10.1111/j.1463-6409.1989.tb00443.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Three new species of monogencans parasitizing hagfish are described:Myxinidocotyle californicagen. et sp.n.,M. japonicasp.n. andLophocotyle novaezeelandicasp.n. The pseudohaptor ofMyxinidocotylehas 8+8 transverse ridges that never attain the radial arrangement characterizingLophocotyleandAcanthocotyle. There are no sclerites in the pseudohaptoral ridges ofMyxinidocotyleandLophocotyle. The male reproductive system ofMyxinidocotyleandLophocotylediffers from that ofAcanthocotylein having a bilateral accessory gland apparatus and an armed copulatory organ. The femrle reproductive system has a large vaginal receptaculum scminis; inMyxinidocotylewith two vagino‐intestinal canals. The uterine pore and the male genital pore are close together and the vaginal pore is situated posterior to them, on the left ventral side of the body. We conclude thatMyxinidocotyle, LophocotyleandAcunrkocotylerepresent different levels of acanthocotylid evolution.Myxinidocotylebeing the most primitive. The family Acanthocotylidac is divided into the subfamilies Myxinidoeutylinae subfam.n., Lophocotylinae and Acanthoeutylina

ISSN:0300-3256    

DOI:10.1111/j.1463-6409.1989.tb00444.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Cultured eggs ofCyathocephalus truncatuswere found to develop optimally at 20°C, but they did not develop at 6°C and above. The oncosphere of the tapeworm has been seen to be a true hexacanth embryo. Specimens of the intermediate host.Gammaurs pulex, were infected by being forced to feed on pieces of lettuce leaves on which infective eggs of the tapeworm were placed. The young drveloping porocercoid was first recovered from the haemocoel ofGammarus pulex5 days after infection. The procercoid was found to reach the infective stage within the amphipod after about ten week

ISSN:0300-3256    

DOI:10.1111/j.1463-6409.1989.tb00445.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Echinderes higginsisp.n. is described from shallow subtidal sand north of the mouth of the Westerscheldt estuary, The Netherlands. The species is compared with other species having the same spine formulac. It appears to be most closely related toE. kristenseniHiggins. 1983 and, to a lesscr extent. toE. riedliHiggins, 1966.Condyldres multispinosus(McIntyre. 1962) is reported from the same locality, the first report of this centroderid kinorhynch since the original description. Some additional information onE. levunderiKarling, 1954 is presented. The presence of lateroventral adhesive tubes on the fourth segment, lateral spines on segment 7 and small additional setae on segment 12 in the male is noted.Echinoderes canariensisGreeff, 1869 andE. agigensBǎcescu, 1968 are consideredspecies inquirendae. The distribution of adult North Sea Kinorhyncha is reviewed. Finally, an up‐dated key. covering 43 valid species ofEchhinderes, is presente

ISSN:0300-3256    

DOI:10.1111/j.1463-6409.1989.tb00446.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Three new species ofProtricomawere found among the material collected during a deep‐sea survey near Corsica:P. Maramphissp.n.,P. mocrocephalasp.n. andP. corsicanasp.n. The new species are characterized by their small body size. a slender cylindrican body with finely annulated body cuticle and a very small hea

ISSN:0300-3256    

DOI:10.1111/j.1463-6409.1989.tb00447.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Namibrema papillatagen. et sp.n. is closely related toNicascolaimus punctatusRicmann, 1986.hnema papillutugen. ct sp.n. is closcly related toNicuwolaimus punctuturRicmann. 1986. The presence of twelve stomatal rugae, the punctated cuticle and the shape of the pre‐anal supplements indicate a relationship with species of the Chromadorina.Axonolaimus deconinckisp.n. is chjaracterized by the complex nature of the gubernaculu

ISSN:0300-3256    

DOI:10.1111/j.1463-6409.1989.tb00448.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

A new species ofSabellariais described from the southeast coast of Brazil and compared with related species known from South or North America.

ISSN:0300-3256    

DOI:10.1111/j.1463-6409.1989.tb00449.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Protodrilus haurakiensissp.n.,P. jouinaesp.n.,P. jägerstenisp.n.,P. submersussp.n. andP. litoralissp.n. from New Zealand andP. gracilissp.n. from Europe are described.Protodrilus jägcrsteni, P. submersusandP. litoralisare sibling species. Sperm dimorphism in all species investigated by the author is recorded for the first time in polychaetes. Two of the three so‐called ‘ecological forms’ ofP. hypoleucusandP. adhaerensare classified as variations of the type species without a particular taxonomic rank. In a table the partly actualized data of all 30 knownProtodrilusspecies are presented, 8 of which are very insufficiently described. Synonyms inProtodrilusand similarities betweenP. rubropharyngeusJägersten andP. flavocapitatusUljanin are m

ISSN:0300-3256    

DOI:10.1111/j.1463-6409.1989.tb00450.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

The male adult, the spermatophore and the spermatozoa ofAtlanta gaudichaudiare described. No parasperm are demonstrable. The ultrastructure of the spermatozoa is shown to differ fundamentally from that of the Archaeogastropoda and Neritopsina and to conform broadly with that of the Mesogastropoda (excepting Cyclophoracea, Viviparacea and Cerithacea), the Neogastropoda and the epitonacean heterogastropods. In having a nuclear fossa, containing the axoneme, which penetrates the entire length of the nucleus as the intranuclear canal, the spermatozoon especially resembles that of some members of the Rissoacea, Littorinacea, Eulimacea, Tonnacea, Volutacea and Conacea. Absence, inAtlantaof type 7 parasperm (sensuKoike 1985), which characterize the Calyptraeacea, Cypraeacea, Tonnacea, Buccinacea, Volutacea (including the Mitracea) and most Conacea, or of type 8 parasperm of the Conidae, contraindicates heteropod relationship with these taxa. Relationship to the Rissoacea cannot be ruled out, though presence of oligopyrene, cusperm‐like sperm in these (Bythiniidae) and pterotracheid heteropods is a questionable indication of affinity. Relationship of heteropods with the Littorinacea is suggested by similarity of the sperm, presence in carinariid heteropods and littorinids of nurse cells, and apparent homology of the male reproductive apparatus in both groups. The latter two similarities require confirmation, however. It is suggested that deposition of spermatophores on the exterior of the female in atlantid heteropods is a primitive mode of sperm transfer compatible with relationship with the Littorinace

ISSN:0300-3256    

DOI:10.1111/j.1463-6409.1989.tb00451.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY